PHP security vulnerability: Internet Access is blocked for all users [closed]

Due to a recent PHP security vulnerability, our administrators blocked user access to the Internet, including Google search.

Users are asked to contact the operators of the necessary websites to inquire whether the PHP vulnerability has been fixed there. This is possible for self-contained websites, but it is generally difficult because users may want to follow a link to another website, which is then not possible.

Is this security measure appropriate, or can other, more user-friendly measures ensure adequate security?